Clinically significant test results require timely follow-up by the clinicians who are responsible to ensure the appropriate response. While critical, acutely life-threatening test results are usually directly communicated to the responsible clinician, the more common and less urgent clinically significant, or actionable;test results have received less standardized management. Unfortunately, failures to correctly manage actionable test results (ATRs) are not infrequent, may be associated with important delays in diagnosis and treatment resulting in patient harm and are among the most common causes of malpractice claims. Patients receiving care by multiple providers across different settings of care are especially vulnerable to mismanaged ATRs. We have designed a safe practice intervention to improve the management of ATRs for ambulatory patients in a large healthcare system. The intervention is based on a highly successful model to improve communication of clinically significant imaging test results in one of our hospitals. The intervention includes enterprise-wide standardization of ATR definitions with stratification of significant results into alert levels, expected timeframes for clinician responses, a set of policies for ATR follow-up, metrics to measure ATR management and performance feedback. Test result alerts will be stratified into 3 levels of urgency: Level 1 alerts for life- threatening results, such as severe hyperkalemia, needing immediate action;Level 2 alerts, such as a positive TB culture, warrant urgent but less immediate attention (within 48 hours);and Level 3 alerts, such as an abnormal Pap test, require less rapid but necessary action (within 6 days). The Level 3 alerts or ATRs are more common and more likely to "fall through the cracks" for follow-up than Level 1 and 2 alerts. We plan to evaluate the effectiveness of our intervention on improving the management of outpatient Level 3 ATRs. The study is a before-and-after design. The primary outcome of interest is the proportion of ATRs documented as acknowledged by the responsible clinician and with appropriate follow-up action(s) such as timely, appropriate testing, change in treatment, referral to a specialist and/or other follow-up actions. We plan to study the implementation of this intervention and create a toolkit for dissemination of our methods that will be generalizable for use by other health care providers. The study goals are well aligned with AHRQ's mission to improve the quality, safety, efficiency, and effectiveness of American health care. PUBLIC HEALTH RELEVANCE: Clinically significant test results require timely clinician follow-up including the non-urgent clinically significant, or actionable, test results that have received less standardized management and attention. Unfortunately, failure to correctly manage actionable test results is not infrequent and may be associated with important delays in diagnosis and treatment and patient harm. We have designed a safe practice intervention to improve the management of actionable test results for ambulatory patients in a large healthcare system.